Program

O.11 -- Oral, NCTP-40

Date: Wednesday, 29 July 2015

Time: 08h50 - 09h10

The pygmy dipole resonance in neutron-rich nuclei

Nguyen Quang Hung (1), Huynh Ngoc Duc (2), and Hoang Anh Tuan Kiet (1)

(1) School of Engineering, Tan Tao University, Duc Hoa, Long An Province, Vietnam; (2) Graduate School, University of Pedagogy, An Duong Vuong, Ho Chi Minh City, Vietnam

The pygmy dipole resonance (PDR), which has been observed via the enhancement of the electric dipole strength $E1$ of atomic nuclei, is studied within a microscopic collective model. The latter employs the Hartree-Fock method with realistic nucleon-nucleon interactions of the Skyrme types plus the random-phase approximation (RPA). The results of the calculations obtained for various even-even nuclei such as $^{16-28}$O, $^{40-58}$Ca, $^{100-120}$Sn, and $^{182-218}$Pb show that the PDR is significantly enhanced when the number of neutrons outside the stable core of the nucleus is increased, that is, in the neutron-rich nuclei. It is found that the relative ratio between the total $E1$ strengths in the low energy region (the PDR region) and the high energy one (the giant dipole resonance – GDR region) does not exceed 4.5 percent. The collectivity of the PDR states will be also discussed.

Presenter: Nguyen Quang Hung